I believe exception for megaminx should be added here. I have witnessed situations where delegate had to make competitor's megaminx illegal because he had more than one tile with logo a couple of times already (including a competitor who was trying to get notable place at Polish Championship...
It's more fair because it doesn't violate 4b)
It's not. The images of scrambled cubes next to scrambles are printed for a reason. It's not Feliks' fault but its fair for other competitors.